When a conventional on-vehicle head-up display is used, there are some cases in which a virtual image is displayed at several meters ahead of a windshield. For this reason, it is difficult for a driver to find at which portion information is displayed and anticipate what information is displayed and which portion of the display is used, and as a result, there is a problem in that it takes time for the driver to grasp the information. Furthermore, there is a problem in that the driver is compelled to move his or her line of sight between the actual view and the windshield so as to look for the information displayed.
Thus, when displaying a guide image of a road by superimposing the guide image upon a scene observed from a mobile body, a head-up display of Patent Document 1, for example, surrounds the guide image with an outline, thereby making a boundary clear between the portion where the guide image is displayed and the scene. In this way, the head-up display can improve the visibility of the guide image.